Ink ribbon cartridge

Abstract: An ink ribbon cartridge includes a detachable ink ribbon spool (2/3) which may be rotatably mounted in a lower shell (4) of the cartridge via first and second shank portions (2a,2b/3a,3b) axially projected from opposite sides of the spool (2/3). The first shank (2b/3b) is of a rod shaped configuration, and includes at least large and small circumference sections which are longitudinally spaced apart. According to such configuration, the spool (2/3) may be installed only in a compatible ink ribbon cartridge having a lower shell (4) including a first bearing member (8) formed with a first bearing groove (8a) rotatably supporting the large circumference section of the first shank (2b/3b) and having a width (B) proportional thereto. A second bearing member (20) is disposed adjacent to, and spaced apart from, the first bearing member (8). The second bearing member (20) includes a second bearing groove (20a) having a width (C) proportional to the small circumference section (22) of the first shank. A third bearing member (7) is formed at a location in said lower shell (4) opposing the first bearing member (8) such that the second shank (2a/3a) of the spool (2/3) is rotatably supported thereby. According to this, various configurations of spools and compatible lower shells may be realized which may be utilized for distinguishing between various types of ink ribbon, etc. Since a spool may only be mounted in a lower shell of compatible configuration, misassembly during manufacturing is prevented. In addition, user error, such as accidental installation of an inappropriate ink ribbon, may be reliably prevented.

Description: BACKGROUND OF THE INVENTION Field of The Invention The present invention relates generally to a ribbon cartridge for a printer apparatus. Particularly, the invention relates to an ink ribbon cartridge for a heat sublimation or vapor type printer in which compatibility between the cartridge and an ink ribbon spool replacably mounted therein may be definitely established at the time of installation. Description of The Related Art Various types of ink ribbon cartridges are available for printing apparatus. Heat vaporization or heat sublimation printers generally use an ink ribbon having a sublimation dye thereon. The ribbon is arranged over a sheet of paper, or the like, on which an image is to be printed. Then a thermal head is energized in conformity with the image contours and is caused to heat the dye contained in the ink ribbon which is sublimated and transferred to the paper according to the thermal energy generated at the thermal head of the printer. Some varieties of printer utilize an ink ribbon cartridge for full color printing in which a printing operation must be repeated several times, for example, three times for printing each primary color, magenta, cyan and yellow, resulting in a full-color image. In some such printers, a single ink ribbon cartridge is utilized in which an ink ribbon spool mounted therein is interchanged for printing each of the different colors. One example of such a conventional interchangable-spool type ink ribbon cartridge is disclosed in United States Patent 5,290,114. The structure of such a cartridge is shown in Figs. 6 and 7. As may be seen, the ink ribbon cartridge comprises an ink ribbon 1 having a predetermined length and wound around a main spool 2. A free end of the ink ribbon 1 is connected to a take-up spool 3 for being wound onto the take-up spool 3 according to printer operation. The cartridge body is formed such that the spools 2,3 are rotatably supported and accommodated in a lower shell 4 to which an upper shell 5 is mounted. The main spool 2 and the take-up spool 3 have substantially identical bearing portions which will be described hereinbelow. Each of the spools 2,3 has a cylindrical shank 2a, 3a at a first end thereof which is slightly larger in diameter than the winding surface of the spools 2, 3. The other ends of each of the spools 2, 3 are provided with a smaller diameter rod-shaped shank 2b, 3b. Flange portions 2c, 2d, 3c, 3d divide the shank ends 2a, 2b, 3a, 3b from the main winding surface of the spools 2, 3 so as to define a winding area for the ink ribbon 1 between pairs of flanges 2c, 2d and 3c, 3d respectively. The lower shell 4 includes a window 6 in a central portion thereof for allowing access of the thermal head (not shown). Annular bearing portions 7,7 are integrally formed with a side wall 4a of the lower shell, and openings defined in the annular bearing portions 7,7 are sized to receive the cylindrical shanks 2a, 3a of the spools 2,3. At the other side of the lower shell 4, second bearing portions 8, 8 are formed for receiving the rod-shaped shanks 2b, 3b of the spools 2,3. The second bearing portions 8, 8 are formed as wall segments within the lower shell, each of the wall segments having U-shaped grooves 8a, 8a respectively formed therein for receiving the shanks 2b, 3b. A reinforcing rib 9 is provided between each of the second bearing portions 8, 8 and a side wall 4b of the lower shell 4, which is opposite the side wall 4a. An upper shell 5 includes a side wall that engages with and is mounted to the side wall 4b and includes a cover portion 11 disposed over the rod-shaped shanks 2b, 3b and having internal structure to cooperate with the second bearing portions 8, 8 to rotatably mount the spools 2, 3 at each end thereof. The structure of the cover portion 11 cooperates with the bearing portions 8, 8 of the lower shell 4, and includes springs 10, 10. For loading the spools 2, 3 into the lower shell 4, the cylindrical shanks 2a, 3a of the main and take-up spools 2, 3 are inserted into the annular bearing portions 7, 7 and the rod-shaped shanks 2b, 3b may simply be dropped into the U-shaped grooves 8a,8a of the second bearing portions 8, 8 for rotatably mounting the spools 2, 3 in the lower shell 4. The upper shell 5 may then be snapped on over the second bearing portions and the ribbon cartridge complete with the second, rod-shaped shanks being secured in a rotatably pressed state. In this known ink ribbon cartridge, referring to Fig. 7, a width B of the U-shaped groove 8a of the second bearing portion 8 for the take-up spool 3 particularly, is made to be slightly larger than a width A of the rod-shaped shank 3b of the spool 3 for assuring easy rotation thereof in a mounted condition. An appropriate ink ribbon cartridge may be selected according to a color to be printed, ribbon/printer compatibility, type of printing to be performed, a winding orientation of the ink ribbon, or of a printing surface thereof, etc. However, in the case of a detachable spool type cartridge wherein the same cartridge body is re-used while ink ribbon spools are changed according to the above-listed criteria, the above-described ink ribbon cartridge structure does not allow a user to verify compatibility of the spool with the cartridge or the printer or printing job to be accomplished. According to this, a user may easily install an inappropriate spool into the lower shell 4 of the cartridge. Such error may cause a printing operation to be flawed, or at worst, may cause jamming or malfunction of the printer due to incompatibility between the ink ribbon ad the type of printer. Thus, it has been required to provide a detachable spool type ink ribbon cartridge in which compatibility of the spool (and thus the ink ribbon) may be reliably established at the time of installation of the spool into the cartridge body. The Japanese patent application published under number 5221068 describes a ink ribbon cassette consisting of a housing containing a ink ribbon unit. The ink ribbon unit consists of a pair of spools and a ink ribbon wound between them. In order to ensure that the ink ribbon cassette will be used only with compatible printers, a label bearing information about the ink ribbon enclosed in the cassette is provided on the cassette housing. This label is read by a optical sensor provided on the printer. Equally, a code ring can be provided, mounted on an end portion of one of the spools, bearing coded information regarding the ink ribbon wound on the spool. This code ring can be rotated by a mechanism provided on the printer in order to enable the code ring information to be read. SUMMARY OF THE INVENTION It is therefore a principal object of the present invention to overcome the drawbacks of the related art. It is a further object of the present invention to provide a detachable-spool type ink ribbon cartridge with simple structure, in which compatibility of the spool may be reliably established at the time of installation of the spool into the cartridge body. In order to accomplish the aforementioned and other objects, a ink ribbon cartridge is provided, comprising: a pair of spools having an ink ribbon wound therebetween around central, axially extending cylindrical winding surfaces thereof and each including first ad second shank portions axially projected from opposing end portions of the respective cylindrical winding surface; a shell including a plurality of bearing portions rotatably supporting the pair of spools at the shank portions; and physically-cooperating compatibility determining means, provided on at least one of said shank portions ad on said shell, adapted physically to prevent a spool which is not compatible with said shell from being inserted therein. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Fig. 1 is a exploded perspective view of a ink ribbon cartridge according to a preferred embodiment of the invention; Fig. 2 is a plan view of a spool configuration according to the invention; Fig. 3 is an enlarged exploded perspective view of a principle feature of the ink ribbon cartridge of Fig. 1; Fig. 4 is a cross-sectional view of a spool installed in a ink ribbon cartridge of the invention; Fig. 5 is a cross-sectional view for explaining installation of the ink ribbon cartridge of the invention into a printer; Fig. 6 is a exploded perspective view of a conventional ink ribbon cartridge; and Fig. 7 is an enlarged exploded perspective view of a main portion of the conventional ink ribbon cartridge of Fig. 6. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, particularly to Figs. 1 - 5, a preferred embodiment of an ink ribbon cartridge according to the invention will be described hereinbelow in detail. In the following description of the preferred embodiment of the invention, like parts will be described with the same reference numbers as the above-described prior art, for ease of understanding. Similarly to the above-described conventional ink ribbon cartridge, an ink ribbon cartridge according to the preferred embodiment of the invention comprises an ink ribbon 1 of a preselected length provided wound on a main spool 2 and rotatably disposed such that the ink ribbon 1 may be wound between the main spool 2 and a take-up spool 3, as may be seen in Fig. 1. An upper shell 5 may be installed over one end of the spools 2, 3. The lower shell 4 includes a window 6 in a central portion thereof for allowing access of the thermal head (not shown). Annular bearing portions 7, 7 are integrally formed with a side wall 4a of the lower shell, openings defined in the annular bearing portions 7, 7 being sized to receive the cylindrical shanks 2a, 3a of the spools 2, 3. At the other side of the lower shell 4, second bearing portions 8, 8 are formed for receiving the rod-shaped shanks 2b, 3b of the spools 2,3. The second bearing portions 8, 8 are formed as wall segments within the lower shell, each of the wall segments having U-shaped grooves 8a, 8a respectively formed therein for receiving the shanks 2b, 3b. Also, as in the above-described conventional structure, one or more reinforcing ribs 9 may be provided between each of the second bearing portions 8, 8 and a side wall 4b of the lower shell 4, which is on a side of the lower shell opposite the side wall 4a and disposed parallel thereto. Referring to Figs. 1 and 3, it may be seen that the lower shell 4 of the invention further includes third bearing portions 20, 20 which further serve as compatibility detecting means for assuring compatibility between the spools 2, 3 and the ink ribbon cartridge, as will be explained hereinbelow. Each of the third bearing portions 20, 20 is formed of substantially L-shaped plate spring material, U-shaped bearing groove 20a is formed in a top edge thereof. The flat upright portion of the third bearing portion 20 is arranged substantially parallel to the second bearing portion 8, separated therefrom by a predetermined gap. The base section of the L-shaped third bearing portion 20 includes mounting holes 20b, 20b and is affixed to a bottom surface of the lower shell 4 by a pair of caulking pins 21, 21 which serve to determine the correct positioning of the third bearing portion 20. The precise positioning of the third bearing portion 20 and the width C of the bearing groove 20a may be established for allowing compatibility of a spool 2, 3 installed in the lower shell to be reliably determined as will be further described hereinlater. Referring now to Figs. 1 - 3 a structure of the spools 2, 3 of the ink ribbon cartridge according to the invention will be set forth in detail. As may be appreciated, each of the spools 2, 3 has a cylindrical shank 2a, 3a at a first end thereof which is slightly larger in diameter than the winding surface of the spools 2, 3, similar to the conventional arrangement. However, according to the invention, the other ends of each of the spools 2, 3 are provided with a two-stage small diameter rod-shaped shank 2b, 3b having a main section of the shank 2b, (3b) which is slightly smaller in diameter than the cylindrical winding surface of the spool, as is conventional, and a smaller diameter section 22 formed in a central portion of the shank 2b (3b). Thus, as best seen in Fig. 2, a shank with essentially two different diameter portions 22 and 2b is provided. The width C of the bearing groove 20a of third bearing portion 20 is thus made to be smaller than than of the bearing groove 8a of the second bearing portion 8 and positioned so as to correspond to the position of the smaller diameter portion 22. Thus, it may be assured that a spool which is not in conformity in these respects with a given lower shell 4, may not be inserted thereinto. As with the previously described related art, flange portions 2c, 2d, 3c, 3d divide the shank ends 2a, 2b, 3a, 3b from the main winding surface of the spools 2, 3 so as to define a central winding area for the ink ribbon 1 between pairs of flanges 2c, 2d and 3c, 3d respectively. For loading the spools 2, 3 into the lower shell 4, the cylindrical shanks 2a, 3a of the main and take-up spools 2, 3 are inserted into the annular bearing portions 7, 7. The larger diameter section of the rod-shaped second shanks 2b, 3b of the spools 2, 3 may easily drop into the Ushaped grooves of the second bearing portions 8, 8 to allow the spools to be simply loaded into the lower shell 4, if the placement of the smaller diameter portion 22 of the rod-shaped shank 2b (3b) is longitudinally positioned on the shank 2b (3b) so as to coincide with the position of the third bearing member 20, as seen in Fig. 4. As noted in the conventional structure, a width B of the U-shaped groove 8a of the second bearing portion 8 of the spool 2 (3) is made to be slightly larger than a width A of the rod-shaped shank 2b (3b) of the spool 2 (3) for assuring easy rotation of thereof in a mounted condition. It will also be noted that the width of the groove 20a of the third bearing portion 20 may be provided greater than the width of the smaller diameter portion 22 for allowing easy installation and rotation of the spool while still establishing a positional relationship for engagement of the smaller diameter portion 22 with the third bearing portion 20 which assures that only a compatible spool 2 (3) will be insertable into the lower shell 4. That is, if for example, it was attempted to install a conventional spool not having the smaller diameter portion 22 formed thereon into the lower shell 4 according to the invention, the narrow width of the bearing groove 20a would prevent insertion of the spool. Thus, the present embodiment provides a simple, low cost and highly reliable method of determining compatibility between between spool and cartridge. This feature has many advantageous applications, particularly, for example, in a manufacturing context wherein different types of ink ribbon cartridges for various different applications are assembled at one factory. Respective positions of the smaller diameter portions 22 of various types of spools, and corresponding respective positioning of the third bearing portion 20 of their compatible shells, may be established such that misassembly becomes impossible, since only the correct, compatible type of spool may be inserted in a particular shell. An upper shell 5 of the ink ribbon cartridge, which may be utilized in the present embodiment, includes a side wall that engages with and is mounted to the side wall 4b and includes semicircular bearing cover portions 11 disposed over each of the rod-shaped shanks 2b, 3b. The upper shell 5 is configured so as to cooperate with the second bearing portions 8, 8 to rotatably mount the spools 2, 3 at each end thereof. The upper shell 5 may be snapped on over the second bearing portions 8, 8 of the ink ribbon cartridge. Hereinbelow, operation of the ink ribbon cartridge according to the invention when installed in a printer for effecting a printing operation will be described in detail with reference to Fig. 5. When the cartridge such as described above is inserted into a printing apparatus (not shown) to effect a printing operation, a drive member 23 of the printer is engaged with the first shank 2a (3a) of the spool 2 (3) for drivingly controlling rotation thereof. As may be seen in the drawing, when the drive member 23 is inserted into the first cylindrical shank 2a, the spool 2 is pushed in the direction of the two-stage small diameter second rod-shaped shank 2b such that the third bearing member 20 is urged to bend slightly. Accordingly, reliable rotational driving of the spool 2 may be assured. Thus an ink ribbon cartridge fulfilling the stated objects of the invention is obtained, yielding various advantageous effects, via a simple structure. Although the above-described preferred embodiment applies to a printer cartridge mounting a pair of spools 2, 3, the structure of the present invention may be applied to other types of ribbon cartridge structures including, for example, cartridges mounting a single spool only, typewriter ribbon cartridges, commercial printing machines, etc. While the present invention has been disclosed in terms of the preferred embodiment in order to facilitate better understanding thereof, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, the invention should be understood to include all possible embodiments and modifications to the shown embodiment which can be embodied without departing from the principle of the invention as set forth in the appended claims.

Claims: An ink ribbon cartridge, comprising: a pair of spools (2,3) having a ink ribbon (1) wound therebetween around central, axially extending cylindrical winding surfaces thereof and respectively including first and second shank portions (2a,2b,3a,3b) axially projected from opposing end portions of said cylindrical winding surfaces; a shell (4) including a plurality of bearing portions (7,8) rotatably supporting said pair of spools (2,3) at said shank portions (2a,2b,3a,3b); and physically-cooperating compatibility determining means (20,22), provided on at least one of said shank portions and on said shell, adapted physically to prevent a spool which is not compatible with said shell from being inserted therein. An ink ribbon cartridge as set forth in claim 1, wherein said compatibility determining means comprises a circumferential groove (22) formed on a selected one of said shank portions ad a member (20) defining a recess (20a) and provided on said shell, a position of said member (20) and a width (C) of said recess (20a) being determined such that said recess (20a) may receive and rotatably support said shank only at the circumferential groove portion (22) thereof. An ink ribbon cartridge as set forth in claim 2, wherein said plurality of bearing portions includes respective first, second and third bearing portions (7,8,20). An ink ribbon cartridge as set forth in claim 3, wherein said third bearing portion (20) is disposed between said first and second bearing portions (7,8). An ink ribbon cartridge as set forth in claim 3, wherein an installation position of said third bearing portion (20) and a size (C) of said circumferential groove (20a) is variable. An ink ribbon cartridge as set forth in claim 3, wherein said third bearing portion (20) is formed of a spring material disposed so as to apply biasing force in a longitudinal direction of an associated one of said spools (2/3). An ink ribbon cartridge as set forth in claim 3, 4, 5 or 6, wherein said compatibility determining means is provided in said third bearing portion (20) disposed between said first and second bearing portions (7,8). An ink ribbon cartridge as set forth in claim 7, wherein - installation position of said third bearing portion (20) and a size (C) of said circumferential groove (20a) is variable. An ink ribbon cartridge as set forth in claim 8, wherein said third bearing portion (20) is formed of a spring material disposed so as to apply biasing force in a longitudinal direction of a associated one of said spools (2,3).

Inventors: KONDO SHINICHI, KONDO, SHINICHI, KONDO, SHINICHI, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1994
Main classification: B41J17
IPC codes: B41J35, B41J17